Unable to insert document with an existing package

Hi, I am unable to insert document with an existing package. My sandbox api key and url work fine. But my company api key and url show errors. My code: import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.InputStream; import com.silanis.esl.sdk.Document; import com.silanis.esl.sdk.DocumentPackage; import com.silanis.esl.sdk.DocumentType; import com.silanis.esl.sdk.EslClient; import com.silanis.esl.sdk.PackageId; import com.silanis.esl.sdk.builder.DocumentBuilder; public class DocumentUpload { public static void main(String[] args) throws FileNotFoundException { System.setProperty("javax.net.ssl.trustStore","C:/Users/pl29158/myprojects/meao/srv/config/wspcerts.jks"); InputStream documentInputStream1= new FileInputStream("C://Users/pl29158/doc/sample_file2.pdf"); Document document = DocumentBuilder.newDocumentWithName("Example Document") //.fromFile("C://Users/pl29158/doc/sample_file2.pdf") .fromStream( documentInputStream1, DocumentType.PDF ) .withId("docuvment1") .withDescription("Sample Document Description") .build(); EslClient eslClient = new EslClient(Utility.API_KEY,Utility.BASE_URL); DocumentPackage documentPackage = eslClient.getPackage(new PackageId("yDJEFQ60jEbNxB7AZ3L6yCBiOCU=")); eslClient.uploadDocument(document, documentPackage); } } errors: Exception in thread "main" com.silanis.esl.sdk.internal.EslServerException: Could not upload document to package. Exception: HTTP POST on URI https://e-signature-uat.pnc.com/a/api/packages/yDJEFQ60jEbNxB7AZ3L6yCBiOCU=/documents resulted in response with status code: [406, Not Acceptable]. Optional details: {"code":406,"entity":null,"message":"Not Acceptable","messageKey":"http.status.406","name":"Not Acceptable","technical":"","packageId":null,"messageLanguage":null} at com.silanis.esl.sdk.service.PackageService.uploadApiDocument(PackageService.java:255) at com.silanis.esl.sdk.service.PackageService.uploadDocument(PackageService.java:240) at com.silanis.esl.sdk.EslClient.uploadDocument(EslClient.java:556) at com.silanis.esl.sdk.EslClient.uploadDocument(EslClient.java:560) at esignLiv.com.DocumentUpload.main(DocumentUpload.java:30) Caused by: com.silanis.esl.sdk.internal.RequestException: HTTP POST on URI https://e-signature-uat.pnc.com/a/api/packages/yDJEFQ60jEbNxB7AZ3L6yCBiOCU=/documents resulted in response with status code: [406, Not Acceptable]. Optional details: {"code":406,"entity":null,"message":"Not Acceptable","messageKey":"http.status.406","name":"Not Acceptable","technical":"","packageId":null,"messageLanguage":null} at com.silanis.esl.sdk.internal.RestClient.execute(RestClient.java:195) at com.silanis.esl.sdk.internal.RestClient.postMultipartFile(RestClient.java:132) at com.silanis.esl.sdk.service.PackageService.uploadApiDocument(PackageService.java:251) ... 4 more